<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
    <script type="text/javascript">
        class IDBError extends Error {
            constructor(errorEvent) {
                const request = errorEvent.target;
                const {error} = request;
                super(error.message);
                this.name = error.name;
                this.errorEvent = errorEvent;
            }

            preventAbort() {
                this.errorEvent.preventDefault();
            }
        }

        class AbortError extends Error {
            get name() { return "AbortError"; }
        }

        function reqAsPromise(req) {
            return new Promise(function (resolve, reject) {
                req.onsuccess = function(e) {
                    resolve(e.target.result);
                };
                req.onerror = function(e) {
                    reject(new IDBError(e));
                };
            });
        }

        function txnAsPromise(txn) {
            return new Promise((resolve, reject) => {
                txn.addEventListener("complete", () => resolve());
                txn.addEventListener("abort", event => {
                    reject(new AbortError());
                });
            });
        }

        function Storage(databaseName) {
            this._databaseName = databaseName;
            this._database = null;
        }

        Storage.prototype = {
            open: function() {
                const req = window.indexedDB.open(this._databaseName);
                const self = this;
                req.onupgradeneeded = function(ev) {
                    const db = ev.target.result;
                    const oldVersion = ev.oldVersion;
                    self._createStores(db, oldVersion);
                }; 
                return reqAsPromise(req).then(function() {
                    self._database = req.result;
                });
            },
            readWriteTxn: function(storeName) {
                return this._database.transaction([storeName], "readwrite");
            },
            readTxn: function(storeName) {
                return this._database.transaction([storeName], "readonly");
            },
            _createStores: function(db) {
                db.createObjectStore("foos", {keyPath: "id"});
            }
        };

        async function main() {
            const storage = new Storage("idb-continue-on-constrainterror");
            await storage.open();
            const txn1 = storage.readWriteTxn("foos");
            const store = txn1.objectStore("foos");
            await reqAsPromise(store.clear());
            console.log("first foo read back", await reqAsPromise(store.get(5)));
            await reqAsPromise(store.add({id: 5, name: "Mr Foo"}));
            try {
                await reqAsPromise(store.add({id: 5, name: "bar"}));
            } catch (err) {
                console.log("we did get an error", err.name);
                err.preventAbort();
            }
            await txnAsPromise(txn1);

            const txn2 = storage.readTxn("foos");
            const store2 = txn2.objectStore("foos");
            console.log("got name from second txn", await reqAsPromise(store2.get(5)));
        }
        main().catch(err => console.error(err));
    </script>
</body>
</html>
 
